Lessons on ‘rock snot’ may stop its spread

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A couple of weeks ago, few Mainers could have told you what didymosphenia geminata was. Fewer would have known that it’s often called “didymo,” or “rock snot.”

Hopefully that’s going to change. And the quicker, the better, for all of Maine’s waters.

The non-native aquatic algae showed up in the upper Connecticut River in Vermont and was noticed a few weeks back. Word quickly spread among anglers, conservationists and fisheries officials across the northeast.

Just a week ago, John Boland, the director of fisheries operations for the Maine Department of Inland Fisheries, admitted that his department was scrambling to learn as much about didymo as it could.

Boland said he didn’t know a whole lot about the algae … and everything he knew sounded bad.

“I’ve read a couple of reports that have come across the Web. They’re from anglers [who say] it’s the worst thing that could ever happen,” Boland said last week, while attending a fisheries hearing. “I don’t know, yet, enough to be able to substantiate that. But like many of these other things, it’s something we really need to be cautious about.”

On Wednesday, the DIF&W, along with the Maine Department of Environmental Protection, showed how seriously they’re taking the didymo threat, issuing a press release, warning that didymo “could threaten Maine’s pristine rivers and streams.”

Didymo, according to the release, can form blooms on the bottom of rocky river beds. Those algae blooms can smother aquatic life forms including insects and native algae.

Didymo attaches itself to rocks with stalks, and masses of the algae 10 to 12 inches thick can grow on the river bottom.

Reports of didymo in Vermont began making the rounds in early July, and were quickly confirmed as factual.

That marked the first time the algae had been documented in the northeastern U.S.

Fisheries biologists were understandably concerned, even before this week’s press release was sent out.

“I think it’s a potentially serious threat,” Rick Jordan said last week. Jordan is the biologist in charge of the state’s Down East fishing region. “It’s not that far from home and it’s in the area where a lot of anglers come from out of state to fish in Maine.”

The problem with didymo, experts explain, is that it’s very resilient, and can be transferred if pieces of it are left on boats, waders, or wading boots.

Some information, Boland pointed out, indicates that didymo can be transported at the spore level, meaning that even concerned boaters or anglers might not see evidence of the algae they could introduce into another piece of water.

And that means that traveling anglers are particularly at risk of inadvertently serving as a means of transportation for the algae.

“It would be a shame to have places like Grand Lake Stream and the East Outlet and the Rapid River and some of those top-quality salmon and trout waters getting [didymo] in it,” Jordan said.

And those are the kind of waters that would likely be at the most risk, in that all are popular destinations for traveling anglers.

“A lot of us anglers move around,” said Greg Ponte, an active Trout Unlimited member said. “Myself, I carry this product in my wading back that I spray my stuff down with, but I don’t even know [if it would kill didymo]. That stuff is for whirling disease.”

Ponte is on the right track, according to Maine fisheries officials.

In the press release the DIF&W and the DEP urged anglers to follow a three-step process when they move from water to water, in order to avoid transporting didymo.

. Check. Before leaving a river or stream, remove all obvious clumps of algae and look for hidden clumps. Leave them at the affected site. If you find any later, do not wash them down drains. Dispose of all material in the trash.

. Clean. Soak and scrub all items for at least one minute in hot (140 degrees Fahrenheit) water, a 2 percent solution of household bleach, or a 5 percent solution of salt, antiseptic hand cleaner or dishwashing detergent.

. Dry. If cleaning is not practical, after the item is completely dry to touch, wait an additional 48 hours before contact or use in any other waterway.

According to Tom Danielson, a biologist with the Maine DEP, there are currently no known ways of eradicating didymo from a river or stream once it has infested that water. Avoiding any spread of the algae is the key.

Danielson said algae in 200 locations on Maine streams and rivers has been tested, and didymo has not been found in Maine waters.

Keeping it that way may take some work, but it’ll certainly be worth the effort. Take the extra time to clean, bleach and dry your waders and wading boots. Pay attention to the water around you. And if you think you’ve seen didymo in a local river, tell someone. Photos of didymo are common on the Internet, and can be easily found there.

You can reach the Maine DEP at 1-800-452-1492 or at milfoil@maine.gov with reports.

John Holyoke can be reached at jholyoke@bangordailynews.net or by calling 990-8214 or 1-800-310-8600.